Gaithersburg's Accessory Structures: The Rules That Matter
Every city handles accessory structures a little differently. In Gaithersburg, Maryland, there are 2 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.
ADU Rules
Gaithersburg allows one accessory dwelling unit per single-family lot under section 24-5.2 of the zoning code. A detached ADU is capped at 800 square feet, or 1,200 square feet with planning commission site-plan approval, while an attached or integral ADU cannot exceed 49 percent of the primary structure's gross floor area. The unit cannot be rented short-term.
Key details: ADUs per lot: One per single-family lot. Detached size cap: 800 sq ft, or 1,200 sq ft with approval. Attached size cap: 49% of primary structure's floor area. Short-term rental: Prohibited in an ADU. Approval process: Minor amendment under § 24-12.6(J).
Building or operating an ADU that exceeds the size caps, sits in the front yard, or is used as a short-term rental violates Chapter 24 and is enforced as a municipal infraction under section 24-15.1 and chapter 1, section 1-9. The city manager or designee can order an illegal ADU vacated or removed, and Planning and Code Administration investigates complaints. Fines run up to the council-set maximum, with an added penalty of up to $1,000 for nonpayment, and section 1-11 allows the city to lien the property for the cost of correcting the violation.
Shed & Carport Rules
Gaithersburg keeps accessory structures like sheds out of the front yard, sets a 2-foot setback for structures 200 square feet or smaller and 10 feet for anything larger, and caps most accessory buildings at 800 square feet and 15 feet in height, all under the zoning code's accessory-structure section.
Key details: Setback (200 sq ft or less): 2 feet from any lot line. Setback (over 200 sq ft): 10 feet from any lot line. Size cap: 800 sq ft unless PC approves more. Height cap: 15 feet. Front-yard placement: Barred for residential uses.
An accessory structure built without meeting the setback, size, or front-yard placement rules is a zoning violation enforced under Article 15 of Chapter 24, punishable as a municipal infraction with fines under section 1-7 of the City Code, and the city manager or designee can require relocation, resizing, or removal, with each day of noncompliance a separate offense.
The Bottom Line
Gaithersburg's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Gaithersburg is broadly strict or permissive.
This guide is based on Gaithersburg's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.